slag
n
1 [U] waste matter that remains after metal has been extracted from ore by smelting 礦渣; 熔渣.
2 [C] (Brit derog sl 貶, 俚) woman who does not look respectable and is regarded as sexually immoral 賤婦; 淫婦. slag, v (-gg-) (phr v) slag sb off (Brit sl 俚) say offensive and critical things about sb, esp unfairly 侮慢或批評某人(尤指無理地)
Now he's left, she's always slagging off her old boss. 因原老板已走了, 她就一個勁兒地褒貶他.